A large-caliber ode to childhood imagination, the Canadian dramatic comedy "I Declare War" is -- above all else -- a film built on a positively inspired idea. Both playful and nostalgic, it's the kind of movie that stands to be appreciated on some level by anyone who has ever pointed a stick and yelled, "Powpowpow!"

That is, pretty much everyone.

Low-budget but high-concept, it offers a view of the hellishness of war as seen through the eyes of a group of wild-eyed adolescents engaged in a very real and very serious -- at least to them -- summertime game of capture the flag. For them, a stick is an AK-47. A small log is a bazooka. And a dye-filled water balloon is the ultimate weapon, a "blood grenade," victims of which suffer the ultimate fate: They must immediately go home, "dead" for the day.

In a surreal flourish that drives home the underlying concept and thrusts audiences into the vivid imaginations of the film's young characters, co-directors Jason Lapeyre and Robert Wilson swap out those ordinary woodland items for real weapons and the "powpowpows" with sounds of real guns, real grenades and real whirlybirds roaring overhead.

This is a game, yes, but to the dozen or so kids engaged in the heat of battle, it's deadly serious stuff.

The rules of engagement are simple: If you're shot with a "gun," you must count to 10 before re-entering the game. If you're hit with a "blood grenade," you're dead. The winning team is the one that captures the other team's flag from a base that cannot be moved in the course of the game.

Young P.K., a pint-sized military enthusiast with an olive drab jacket and a flinty, knowing gaze, has never lost at this game -- a streak his opponents are determined to end on this particular afternoon of infamy. When one of the more unpredictable foot soldiers goes Col. Kurtz on the others, however -- fragging his commanding officer with a blood grenade and seizing command -- nobody's sure what will happen.

Technically, "I Declare War" is a comedy, but a great deal of the fun is in the way Lapeyre and Wilson -- as well as their actors -- approach it all with hardly a shred of irony. That starts with the characters' in-the-field nicknames, including "Joker" -- a name plucked directly from Stanley Kubrick's "Full Metal Jacket" -- and "Altar Boy," and continues through to their "Art of War" tactics and the odd cigarette tucked behind the ear.

The performances of the young actors are a touch hit and miss, but all make laudable contributions to what ends up being an impressively sprawling cast, stocked with nearly a dozen distinct characters.

If there's a complaint -- aside from an over-reliance on F-bombs (we get it, they think they're real soldiers) -- it's that Lapeyre and Wilson don't really have a whole lot to say, making "I Declare War" feel like little more than a well-conceived gimmick film. Sure, it's built around a great idea, and it touches on the treacherousness of friendship as well as the loss of childhood innocence, but it never really feels as if it lives up to its full potential in a truly resonant way.

In other words, while it's enjoyable enough to watch, there's no slam-dunk takeaway here. "I Declare War," which opens Friday (Sept. 20) for a weeklong run at the Zeitgeist Multi-Disciplinary Arts Center, is a cute little feature film, but it would have been just as enjoyable -- maybe even more -- as a 45-minute short.

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I DECLARE WAR3 stars, out of 5

Snapshot: A low-budget, high-concept dramatic comedy about a group of adolescents engaging in what is, to them at least, a very real summertime game of capture the flag.

What works: It's built on an inspired concept, as directors Jason Lapeyre and Robert Wilson thrust the audience into their characters' imaginations by replacing their sticks and "powpowpows" with real weapons.

What doesn't: The performances from the young cast are hit or miss, and the whole idea never quite feels developed as well as it could have been.